[0001] This invention relates to a friction hinge assembly for mounting a closure member,
such as an openable window, on a fixed frame.
[0002] Friction hinge assemblies are well known in the art, and will therefore not be described
in detail herein. Essentially, a fixed guide track is provided, which is usually secured
to a frame member of a fixed frame, and a 4 or 5 bar type of linkage is connected
to the guide track and has one arm secured to a frame element of a closure member,
e.g. a top hung or side hung window.
[0003] The linkage is usually connected to the guide track by a slide block which is moveable
lengthwise of the guide track during opening and closing movement of the linkage.
Also, to provide greater security (and for sealing) when in the closed position, it
is usual to provide some type of inter-engagement between a retainer arrangement on
the guide track and a projecting part of the linkage, so as to resist any unauthorised
attempt at forced opening of the window from externally of the window e.g. by an intruder
entering a jemmy or the like between the fixed frame and the moveable window frame
with a view to prising them apart.
[0004] Existing designs of retainer arrangement on a guide track can take the form of so-called
end caps, which are usually moulded from plastics material and which are pressfitted
into one end of the guide track. The projecting part of the linkage is usually mounted
on one end of the arm which is secured to the frame element of the moveable frame,
and which moves into engagement with the end cap as the moveable frame moves to a
fully closed position.
[0005] The end cap often, being made of plastics material, and press-fitted into the end
of the guide track, does not provide a very robust construction, and therefore is
liable to fail under load, either by fracturing or tearing of the cap, and / or by
forced displacement of the cap from the guide track. Given the ever increasing customer
demand for greater security, there is a need to provide increased security at this
potentially vulnerable region which is located close to the hinge line (usually defined
jointly by a pair of cooperating friction hinge assemblies).
[0006] The invention therefore seeks to meet this need by providing a more robust retainer
arrangement on the guide track, and a co-operative projecting part on the linkage,
which can withstand attempts at forced intrusion and also meet higher test standards
which are being set.
[0007] According to the invention there is provided a friction hinge assembly for mounting
an openable closure member, such as a top hung or side hung window, on a fixed frame,
and which comprises a guide track which is securable to a fixed frame member of the
fixed frame and a linkage which is connected to the guide track so as to be moveable
between open and closed positions relative to the guide track and which has a mounting
arm which is securable to a frame element of the moveable closure member, and in which:
the guide track has a retainer secured to one end of the guide track and having an
upstanding retaining formation;
the mounting arm has a hook secured to one end and which is moveable into engagement
with the upstanding retaining formation as the linkage moves to the closed position;
the engagement between the hook and the retaining formation provides a resisting force
which is directly opposite to any separating force applied between the fixed frame
and the moveable frame in the region of the hinge axis provided by the friction hinge
assembly; and,
the greater the separating force which is applied, the more will the hook move into
captive engagement with the retaining formation to provide an enhanced resisting force.
[0008] The retaining formation and the co-operative engagement of the hook will be arranged
in such a way as to provide an enhanced resisting force when required, and this arrangement
can be achieved in a number of ways.
[0009] In one preferred arrangement, the retainer has a cap arranged to overlie at least
part of the hook in the closed position, so as to resist relative separation in a
direction perpendicular to the guide track and generally in the plane of the closure
member. Also. the construction is such as to prevent buckling by preventing movement
in line with the track.
[0010] The cap is preferably connected to a retaining leg which is shaped to engage in the
recess defined by the hook, and to be engageable with the hook in such a way as to
have ever increasing engagement and provide an enhanced resisting force as the separating
force increases.
[0011] To provide a particularly strong retainer, it is preferred that the retainer is a
metal fabrication.
[0012] A friction hinge assembly according to the invention is particularly, though not
exclusively, suitable for use with a top hung window frame. However, it may also be
used with a side hung window assembly.
[0013] A preferred embodiment of friction hinge assembly according to the invention will
now be described in detail, by way of example only, and with reference to the accompanying
drawings, in which:
Figure 1 is a plan view of a friction hinge assembly, suitable for mounting a top
hung (or a side hung) openable window on a fixed frame, and showing the component
parts of the assembly in a partly open position;
Figure 2 is a plan view of the components of the assembly, but in which an operating
linkage (which is connectable to a moveable window frame) overlies a fixed guide track
to be mounted on a frame member of the fixed frame, (this is the position taken by
the components in the closed position); and,
Figure 3 is a perspective and diagrammatic illustration of a pair of hinge assemblies
mounting a top hung window frame on a fixed frame, with the window frame shown in
a partly open position.
[0014] Referring first to Figure 1 of the drawings, a friction hinge assembly according
to the invention is designated generally by reference 40, and is intended to mount
an openable closure member, such as a top hung or side hung window, on a fixed frame.
The assembly 40 comprises a fixed guide track 41 which is securable to a fixed frame
member of the fixed frame, and a linkage, designated generally by reference 42, which
is connected to the guide track 41 so as to be moveable between open and closed positions
relative to the guide track and which has a mounting arm 43 which is securable to
a frame element of the moveable closure member.
[0015] The linkage 42 is a 4 or 5 bar type linkage, having mounting arm 43 and a short connecting
arm 44 pivoted at one end 45 to one end of the arm 43, and pivoted at its opposite
end 46 to a moveable slide block 47 which is moveable lengthwise of the guide track
41 during opening and closing movement of the linkage 42.
[0016] However, to function as an egress hinge, block 47 may be a fixed mounting block,
and the fixed pivot mounting for arm end 50 can be replaced by a slidable mounting
block (not shown).
[0017] The linkage 42 also includes a long connecting arm 48, pivoted at one end 49 to the
mounting arm 43, and at its opposite end 50 to a fixed pivot mounting on one end of
the guide track 41.
[0018] A control arm 51 extends substantially parallel to mounting arm 43, and is pivoted
at one end 52 to the slide block 47, and at its opposite end 53 to the long connecting
arm 48. Arms 43 and 51 therefore form an approximate parallelogram linkage, which
controls the opening and closing movement of the linkage 42, in conjunction with pivotal
movement of the long connecting arm 48 about pivot 50.
[0019] The guide track has a retainer secured to an end of the guide track opposite to the
end provided with the pivot mounting 50, and the retainer is designated generally
by reference 54. The retainer 54 is secured to the end of the guide track, and has
a mounting portion 55 slidably received and held captive in the in-turned side walls
56 of the guide track 41 and an upstanding retaining formation 57 which is engageable
by a projecting part provided on the end of the mounting arm 43, as will be described
in more detail below.
[0020] Thus, the mounting arm 43 has a hook 58 secured to one end thereof and which is moveable
into engagement with the upstanding retaining formation 57 as the linkage 42 moves
to the closed position.
[0021] Figure 1 shows the linkage 42 in an open position, whereas Figure 2 shows the linkage
42 overlying the guide track 41, which is the position which they take up when the
closure member (e.g. a top hung window) has been moved to the fully closed position.
[0022] The engagement between the hook 58 and the retaining formation 57 is such as to provide
a resisting force which is directly opposite to any separating force which may be
applied between the fixed frame and the moveable frame in the region of the hinge
axis which is provided by the friction assembly. Furthermore, the arrangement is such
that the greater the separating force which is applied (e.g. by a potential intruder,
or during standard safety tests) the more will the hook 58 move into captive engagement
with the retaining formation 57 to provide an enhanced resisting force.
[0023] Any suitable arrangement of the retaining formation 57 and the cooperative engagement
of the hook 58 can be provided, so as to give an enhanced resisting force when required,
and progressively increasing inter-engagement as a consequence of increased separating
force.
[0024] In the preferred arrangement, the retainer 54 has a cap 59 which overlies at least
part of the hook 58 in the closed position, so as to resist relative separation in
a direction perpendicular to the guide track 41 and generally in the plane of the
closure member.
[0025] In particular, when a force is applied perpendicular to the side of the track, the
hook engages cap 59 so as to prevent any downward movement (possibly resulting from
buckling of arms 43, 44).
[0026] The cap 59 is connected to a retaining leg 60 which is shaped to engage the recess
61 defined by the hook 58, and to be engageable with the hook in such a way as to
have ever increasing engagement, and to provide an enhanced resisting force, as the
separating force increases.
[0027] To provide a particularly strong retaining arrangement, it is preferred that the
arrangement is a metal fabrication.
[0028] The illustrated embodiment therefore provides a hook which is directly fixed to the
openable window frame, by being fixed in the region of the junction between the mounting
arm 43 and the short connecting arm 44, and extending along the line of the mounting
arm 43. The purpose of the hook is to engage on a robust assembly of cap (54) fitted
on to the guide track 41, which is fixed to the outer frame.
[0029] When a load is applied to the corner of the window, the hook is forced on to the
retaining leg of the cap. This action prevents the openable window (sash) from becoming
dis-engaged from the retaining leg of the cap, which holds the sash and the frame
in their respective positions and prevents the friction hinge (stay) from buckling
and failing under load.
[0030] The only approved way to open the window is to apply a force at the bottom of the
hinge, as shown by the arrow in Figure 2. This allows the geometry of the hinge assembly
to rotate around the retaining leg, and then withdraw from engagement therewith as
the window opens. Normally, any intruder attempting forced separation between the
window frame and the fixed frame will not be able to apply the separating force at
this region, and particularly because it will usually be strongly resisted by separate
espagnolette and other types of locking systems provided in this region of the window
and frame assembly.
[0031] The illustrated arrangement of the engagement between the hook and the retaining
arrangement is unique in not requiring either fixing, or a supporting lug to be inserted
along the hinge line.
[0032] Figure 3 shows a typical top hung window frame 62, mounted on a fixed frame 63 via
a pair of friction hinge assemblies 64, and showing a hinge line 65 defined by the
friction hinge assemblies 64, and also the line of action of any load which may be
generated by an intruder seeking forced separation between the window 62 and the frame
63 (when in the closed position), or any test load applied during safety tests.
[0033] The embodiment of security friction hinge assembly disclosed herein may include features
of the restricted hinge assembly disclosed in our co-pending patent application filed
on the same day as this application.
1. A friction hinge assembly (40) for mounting an openable closure member (62), such
as a top hung or side hung window, on a fixed frame (63), and which comprises a guide
track (41) which is securable to a fixed frame member of the fixed frame and a linkage
(42) which is connected to the guide track (41) so as to be moveable between open
and closed positions relative to the guide track (41) and which has a mounting arm
(43) which is securable to a frame element of the moveable closure member (62), and
in which:
the guide track (41) has a retainer (54) secured to one end of the guide track and
having an upstanding retaining formation (57);
the mounting arm (43) has a hook (58) secured to one end and which is moveable into
engagement with the upstanding retaining formation (57) as the linkage (42) moves
to the closed position;
the engagement between the hook (58) and the retaining formation (57) provides a resisting
force which is directly opposite to any separating force applied between the fixed
frame (63) and the moveable frame (62) in the region of the hinge axis (65) provided
by the friction hinge assembly (40); and,
the greater the separating force which is applied, the more will the hook (58) move
into captive engagement with the retaining formation (57) to provide an enhanced resisting
force.
2. A friction hinge assembly according to claim 1, in which the retainer (54) has a cap
(59) arranged to overlie at least part of the hook (58) in the closed position, so
as to resist relative separation in a direction perpendicular to the guide track (41)
and generally in the plane of the closure member (62), and / or to resist buckling
under load applied generally perpendicular to the side of the track (41).
3. A friction hinge assembly according to claim 1 or 2, in which the retaining formation
(57) includes a retaining leg (60) which is shaped to engage in the recess (61) defined
by the hook (58), and to be engageable with the hook (58) in such a way as to have
ever increasing engagement and provide an enhanced resisting force as the separating
force increases.
4. A friction hinge assembly according to any one of claims 1 to 3, in which the retainer
(54) is a metal fabrication.